1. Field of the Invention
The present invention relates to a cost efficient spectrum-sliced fiber amplifier light to be used with practical wavelength-division-multiplexed (WDM) systems for both long-distance (.about.100 km) and local loop applications.
2. Information Disclosure Statement
Recent achievements in optical amplifiers revitalize the practicality of wavelength-division-multiplexed (WDM) systems for both long-distance transmission and local-loop applications. However, WDM systems are envisioned to have a multiple number of transmitter lasers operating at different wavelengths. Thus, these transmitter lasers should be wavelength-selected for each channel and controlled to operate at a specific wavelength to the end of a system's lifetime. However, this process would increase cost and complexity.
There have been a few attempts to overcome this problem by using broadband lights. For example, the broadband light from 1.3-.mu.m light emitting diodes (LEDs) or superluminescent diodes (SLDs) was "spectrum-sliced" using grating-based demultiplexers and used in WDM systems. Thus, there was no need for wavelength-selecting transmitter lasers and identical LEDs were used for every channel. However, the transmission rates were limited to 2 Mb/s-150 Mb/s over the distances less than 7 km due to the insufficient power inherent in LEDs. Recently, the transmission distance has been extended to 110 km at 140 Mb/s using 1.5-.mu.m SLDs and an erbium-doped fiber amplifier (EDFA).
M. H. Reeve, A. R. Hunwicks, W. Zhao, S. G. Methley, L. Bichers and S. Hornung, "Led Spectral Slicing For Single-Mode Local Loop Applications", Electronics Letters, Vol. 24, No. 7 (Mar. 31, 1988), pp. 389-390, and S. S. Wagner and T. E. Chapuran, "Broadband High-Density WDM Transmission Using Superluminescent Diodes", Electronics Letters, Vol. 26, No. 11 (May 24, 1990), pp. 696-697, describe "spectrum-sliced" light emitting diodes (LEDs) and superluminescent diodes (SLDs) using grating-based demultiplexers.
Further, an article, P. D. D. Kilkelly, P. J. Chidgey, and G. Hill, "Experimental Demonstration of a Three Channel WDM System Over 110 km Using Superluminescent Diodes", Electronics Letters, Vol. 26, No. 20 (Sep. 27, 1990), pp. 1671-1673, addressing transmission distance using SLDs and an erbium-doped fiber amplifier (EDFA) has been written.
However, none of these articles considers a system for spectrum-sliced fiber amplifier light for multi-channel WDM applications encompassed by the present invention.